This invention relates to control of fluid in relatively high pressure fluid conducting lines and more particularly to a cushioned closing action shutoff valve.
1. Field of the Invention
A globe or single seat type valve interposed in a relatively high pressure fluid conducting pipe line, when moved to a closed position by high pressure fluid collapsing a pressure responsive pin the valve in the globe or single seat type valve moves from a fluid passageway fully open position to a completely closed fluid passageway position in milliseconds.
If the fluid in the line is a gas this presents no problem, however, if the fluid is a liquid this sudden flow stoppage of fluid in a line of several miles in length creates tremendous pressure in the pipeline which may equal twice the pressure which caused the valve to close in the first place. This excessive pressure as a result of a globe or single seat type valve closing quickly is highly undesirable.
This invention solves this problem by dampening the movement of the valve toward its seat in a closing action.
2. Description of the Prior Art
The most pertinent patents are believed to be my U.S. Pat. No. 5,067,511 issued Nov. 26, 1991 for HIGH PRESSURE FLUID EMERGENCY SHUTDOWN VALVE.
This patent features a valve body connected with a fluid conductor in which a valve moved toward its seat by fluid pressure includes an elongated valve stem projecting through a valve bonnet to collapse a pin due to fluid pressure on the unbalanced valve stem area referenced to atmospheric pressure giving an axial force to buckle the restraining pin for permitting the valve to close with its seat and stop fluid flow through the valve body.
This invention provides a valve body similarly having a valve fluid pressure moved toward its seat in which the valve has an elongated stem connected with a dashpot which cushions valve impact on its seat in response to high pressure fluid collapsing a pin and moving the valve to close with its seat.